The invention is directed to an apparatus for the partial, electrolytic coating of individual metallic parts, especially pins, switches and belts for electrical contacts, by partial immersion in a liquid bath, consisting essentially of an electrolyte tank, a conveyor chain for fastening and contacting the parts to be coated, a coating apparatus and a withdrawing apparatus.
Individual parts, especially pins for electrical contacts are generally partially coated (plated) electrolytically, especially gold plated, by arranging in a row on a conveyor device, contacting and immersing in an electrolytic bath. The electrolytic coating or plating takes place in this case up to the depth of immersion of the part in the bath. For the economical manufacture of such pins there is frequently resorted to so-called pin bars arranged in rows or synthetic conveyers.
The core problem in this process for partial coating consists in the contacting of the workpiece, especially if the coating should be in continuous operation, and because of economical pass through times which mean that it must be operated with maximum currents and bath temperatures.
There is already known from German OS No. 1796017 an electrolytic apparatus for the partial coating of such parts in which the workpieces hanging on contacting and conveying cars are led through the bath. The cars with the help of rollers are carried in a fixed cathode guide rail over the electrolytic tank which does not quarantee that there can be kept an exact depth of immersion of the parts to be coated. Besides contacting difficulties occur.
In German OS No. 2460694 there are described contacting and conveying cars with binding rods for receiving two rows of pin bars which are joined together by hinges for the formation of an endless conveying chain. With the help of rolls they are carried in a guide rail and contacted via carbon brushes with a cathode bar. Thereby the conveying chain is driven with the help of two polygonal wheels which are adjusted to the conveying cars. However, only two row binding rods can be coated on this apparatus, but not single-row binding pins, switches or belts.
Therefore, it was the problem of the present invention to make an apparatus for the partial electrolytic coating of individual metal parts, especially pins, switches and belts for electrical contacts, by partial immersion in a liquid bath consisting essentially of an electrolytic tank, a conveying chain for fastening and contacting the parts to be coated, a coating and withdrawing device which guarantees a constant depth of immersion in the liquid bath of the parts to be coated and also quarantees a reliable contacting.